A current internal antenna used as an internal antenna in cellular mobile telephones is the Planar Inverted-F antenna (PIFA). This type of antenna comprises an antenna element 12 that is parallel to a ground plane that connects the ground point and feed point together towards one end of the antenna element. These antennas suffer from a number of disadvantages. They have at most two operational resonant frequencies which could be used at the cellular bands. The separation between the antenna element and the ground plate needs to be kept fairly large (˜7 mm) in order to maintain a satisfactory bandwidth.
It would be desirable to provide a more compact antenna particularly one with a low profile.
It would be desirable to provide an antenna with three operational resonant frequencies, which could be used at the cellular bands